A widespread but localised species of ancient woodland and other places with old trees. Two very different colour forms exist – the ‘type’ form with a white tail and broad yellow collar (a superb mimic of the Tree Bumblebee, Bombus hypnorum) and the all-yellow form ‘oxycanthae’ (a mimic of carder bumblebees like B. pascuorum). The latter is very similar to another hoverfly, the late-flying Arctophila superbiens.
Both sexes visit flowers like Hawthorn and Bramble. Females are often seen flying slowly around stumps and the bases of old trees in shaded locations. They give a superb impression of a small bumblebee looking for its nest . The larvae develop in wet decaying tree roots and probably old rotten stumps, typically of broadleaved species, though coniferous species can be used abroad…Steve Falk